Alternative oxidase



  The alternative oxidase is an enzyme that forms part of the electron transport chain in plants, as well as some fungi, protists and possibly some animals.[1][2] Sequences similar to the plant oxidase have also been identified in bacterial genomes.[3][4]

The oxidase provides an alternative route for electrons passing through the electron transport chain to reduce oxygen. However, as several cyanide.[5]

Function

This oxidative stress.[9]   Unusually, the bloodstream form of the protozoan parasite Trypanosoma brucei, which is the cause of sleeping sickness, depends entirely on the alternative oxidase pathway for cellular respiration through its electron transport chain.[10][11] This major metabolic difference between the parasite and its human host has made the T. brucei alternative oxidase an attractive target for ascofuranone inhibits the T. brucei enzyme and cures infection in mice.[14][15]

In fungi, the ability of the alternative oxidase to bypass inhibition of parts of the electron transport chain can contribute to fungicide resistance. This is seen in the strobilurin fungicides that target complex III, such as azoxystrobin, picoxystrobin and fluoxastrobin.[16] However, as the alternative pathway generates less ATP, these fungicides are still effective in preventing spore germination, as this is an energy-intensive process.[17]

Structure and mechanism

The alternative oxidase is a tyrosine residue.[21]

See also

References

  1. ^ McDonald A, Vanlerberghe G (2004). "Branched mitochondrial electron transport in the Animalia: presence of alternative oxidase in several animal phyla". IUBMB Life 56 (6): 333-41. PMID 15370881.
  2. ^ Sluse FE, Jarmuszkiewicz W (1998). "Alternative oxidase in the branched mitochondrial respiratory network: an overview on structure, function, regulation, and role". Braz. J. Med. Biol. Res. 31 (6): 733-47. PMID 9698817.
  3. ^ McDonald AE, Amirsadeghi S, Vanlerberghe GC (2003). "Prokaryotic orthologues of mitochondrial alternative oxidase and plastid terminal oxidase". Plant Mol. Biol. 53 (6): 865-76. PMID 15082931.
  4. ^ Atteia A, van Lis R, van Hellemond JJ, Tielens AG, Martin W, Henze K (2004). "Identification of prokaryotic homologues indicates an endosymbiotic origin for the alternative oxidases of mitochondria (AOX) and chloroplasts (PTOX)". Gene 330: 143-8. PMID 15087133.
  5. ^ Moore AL, Siedow JN (1991). "The regulation and nature of the cyanide-resistant alternative oxidase of plant mitochondria". Biochim. Biophys. Acta 1059 (2): 121-40. PMID 1883834.
  6. ^ Juszczuk IM, Rychter AM (2003). "Alternative oxidase in higher plants". Acta Biochim. Pol. 50 (4): 1257-71. PMID 14740012.
  7. ^ Vanlerberghe GC, McIntosh L (1997). "Alternative oxidase: From Gene to Function" 48: 703-734. PMID 15012279.
  8. ^ Ito Y, Saisho D, Nakazono M, Tsutsumi N, Hirai A (1997). "Transcript levels of tandem-arranged alternative oxidase genes in rice are increased by low temperature". Gene 203 (2): 121-9. PMID 9426242.
  9. ^ Maxwell DP, Wang Y, McIntosh L (1999). "The alternative oxidase lowers mitochondrial reactive oxygen production in plant cells". Proc. Natl. Acad. Sci. U.S.A. 96 (14): 8271-6. PMID 10393984.
  10. ^ Chaudhuri M, Ott RD, Hill GC (2006). "Trypanosome alternative oxidase: from molecule to function". Trends Parasitol. 22 (10): 484-91. PMID 16920028.
  11. ^ Clarkson AB, Bienen EJ, Pollakis G, Grady RW (1989). "Respiration of bloodstream forms of the parasite Trypanosoma brucei brucei is dependent on a plant-like alternative oxidase". J. Biol. Chem. 264 (30): 17770-6. PMID 2808350.
  12. ^ Nihei C, Fukai Y, Kita K (2002). "Trypanosome alternative oxidase as a target of chemotherapy". Biochim. Biophys. Acta 1587 (2-3): 234-9. PMID 12084465.
  13. ^ Grady RW, Bienen EJ, Dieck HA, Saric M, Clarkson AB (1993). "N-n-alkyl-3,4-dihydroxybenzamides as inhibitors of the trypanosome alternative oxidase: activity in vitro and in vivo". Antimicrob. Agents Chemother. 37 (5): 1082-5. PMID 8517695.
  14. ^ Minagawa N, Yabu Y, Kita K, Nagai K, Ohta N, Meguro K, Sakajo S, Yoshimoto A (1997). "An antibiotic, ascofuranone, specifically inhibits respiration and in vitro growth of long slender bloodstream forms of Trypanosoma brucei brucei". Mol. Biochem. Parasitol. 84 (2): 271-80. PMID 9084049.
  15. ^ Yabu Y, Yoshida A, Suzuki T, Nihei C, Kawai K, Minagawa N, Hosokawa T, Nagai K, Kita K, Ohta N (2003). "The efficacy of ascofuranone in a consecutive treatment on Trypanosoma brucei brucei in mice". Parasitol. Int. 52 (2): 155-64. PMID 12798927.
  16. ^ Miguez M, Reeve C, Wood PM, Hollomon DW (2004). "Alternative oxidase reduces the sensitivity of Mycosphaerella graminicola to QOI fungicides". Pest Manag. Sci. 60 (1): 3-7. PMID 14727735.
  17. ^ Avila-Adame C, Köller W (2003). "Impact of alternative respiration and target-site mutations on responses of germinating conidia of Magnaporthe grisea to Qo-inhibiting fungicides". Pest Manag. Sci. 59 (3): 303-9. PMID 12639047.
  18. ^ Berthold DA, Stenmark P (2003). "Membrane-bound diiron carboxylate proteins". Annual review of plant biology 54: 497-517. PMID 14503001.
  19. ^ Berthold DA, Andersson ME, Nordlund P (2000). "New insight into the structure and function of the alternative oxidase". Biochim. Biophys. Acta 1460 (2-3): 241-54. PMID 11106766.
  20. ^ Berthold DA, Voevodskaya N, Stenmark P, Gräslund A, Nordlund P (2002). "EPR studies of the mitochondrial alternative oxidase. Evidence for a diiron carboxylate center". J. Biol. Chem. 277 (46): 43608-14. PMID 12215444.
  21. ^ Affourtit C, Albury MS, Crichton PG, Moore AL (2002). "Exploring the molecular nature of alternative oxidase regulation and catalysis". FEBS Lett. 510 (3): 121-6. PMID 11801238.


v • d • e
Diphenol family Coenzyme Q - cytochrome c reductase - Catechol oxidase - Laccase - Alternative oxidase
v • d • e
Mitochondrial Complex IV - Alternative oxidase - Electron-transferring-flavoprotein dehydrogenase
v • d • e
Ethanol Formation
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Alternative_oxidase". A list of authors is available in Wikipedia.